Liverpool manager Rafael Benitez has expressed frustration at his club's failure to agree a £110m investment deal with the New York-based Rhône Group and suggested, ahead of the Europa League quarter-final tie with Benfica tonight, that he has taken the club as far as he can under the current financial limitations.

Liverpool manager Rafael Benitez has expressed frustration at his club's failure to agree a £110m investment deal with the New York-based Rhône Group and suggested, ahead of the Europa League quarter-final tie with Benfica tonight, that he has taken the club as far as he can under the current financial limitations.

"If we don't have new investors it will be difficult to go one step further," the Liverpool manager said yesterday, disclosing that the collapse of the Rhône offer, when a deadline imposed by the fund management company expired at midnight on Monday, had shattered the optimism he had started to feel in recent months about the club's financial future. "For six months I was really optimistic, especially about this group, because they were one of the groups who were there," said the Spaniard, who is understood to have met with Rhône. "But they are not there now. The Rhône Group is not there."

Benitez's observations will not endear him to his managing director, Christian Purslow, who was appointed last year to raise the money to pay off £100m of debt in line with the demands of the club's bankers Royal Bank of Scotland (RBS). Purslow could have done without the manager's intervention 48 hours after the latest target date for new cash had passed. Benitez said the reasons for Rhône's departure from the table had not been communicated to him, and though there is talk of two other prospective buyers in the background, he clearly feels he has heard it all before. "I have heard a lot of talk about investors for six months," he said. "I have had some talks myself with possible investors and still we are here and working hard but without confirmation."

Liverpool are unwilling to discuss whether the Rhône offer has been withdrawn, but it has, with the current owners Tom Hicks' and George Gillett's reluctance to cede overall control seemingly the stumbling block.

Benitez's comments raise further questions about whether he will be around at Anfield to experience a new financial era. There certainly will be a new one of some description from July, by which time RBS will want to see £100m of the debt heaped upon the club by Hicks and Gillett paid back. Rhône's investment would have gone straight to the bank and RBS is unlikely to allow prevarications from Hicks and Gillett beyond July, by which time the current debts must be refinanced.

Hicks' and Gillett's ability to meet interest payments under the current arrangements will be tested to the extreme if Benitez fails to deliver them the £20m bonanza of Champions League football next season, and it remains to be seen how the manager's decision to withdraw Fernando Torres after an hour at St Andrew's on Sunday – during the 1-1 draw that leaves fourth place looking remote – will be viewed when his position is reviewed this summer. Benitez acknowledged yesterday that some of his players doubted the decision, though he would not discuss whether Europa League success was his priority now. "Maybe one or two players were not happy but the team performance was one of our best away from home," the manager said.

He was presumably talking about Torres, who shook his head as he trudged off, though the striker's comments this week that the club had become "messed up" last summer when "circumstances dictated" that Xabi Alonso, Alvaro Arbeloa and Sami Hyypia had to be sold, teed up the manager to discuss the financial position. Conspiry theorists might say Torres provided a useful distraction for his manager from other issues.

Benitez said his position was a long way from Pep Guardiola's. "I was watching Barcelona against Arsenal," he disclosed. "Barcelona are a massive club with a massive stadium. They can spend big money in the transfer window. That is the way to do things if you want to compete at the maximum level. So we have to improve in a lot of things. We balanced the books this year and now we need to go forward. We have been wheeling and dealing for six years, keeping the club at a good level. Now it is time to just focus on football and then we will see what happens."

It all adds up to yet another chaotic preamble to a match night. The last Europa League home tie, against Lille, was preceded by Albert Riera's outburst at the "sinking ship", as he described Liverpool, prompting Benitez to comment on his abysmal timing.